Specializes in Duramax/Allison components and sells the fluid for around per gallon at Dmaxstore . Petroleum Services Trucking company ClosedWoodward, OK

Offers 1-gallon jugs for around and 5-gallon pails for about $218 at Triple R Truck Parts . FleetPride

Best for bulk orders, offering everything from 1-gallon jugs to 55-gallon drums at Petroleum Service Company . Castrol® TranSynd 668 Synthetic Transmission Fluid - 1 gal

: Lists the fluid and sometimes offers 20% off eligible ship-to-home items with codes like DEAL4SPRING at AutoZone . Specialized Truck & Performance Parts

If you need larger quantities (like 5-gallon pails) or specific diesel expertise: Triple R Truck Parts Truck parts supplier ClosedEddystone, PA

These stores often have the best availability for individual 1-gallon jugs: